WASHINGTON  More than 90 percent of the 23,600 annual deaths caused by pollution from aging coal-fired power plants could be prevented if the U.S. government adopted stricter rules, according to a study by environmental groups.

The report criticized the Bush administration for trying to roll back existing clean air laws. It said such a rollback would result in nearly 4,000 more annual deaths from asthma, heart attacks, and other ailments linked to coal plant emissions.

"The Bush air pollution plan represents a step backward from simply enforcing current law," said Angela Ledford, director of Clear the Air, a coalition that includes the National Environmental Trust, the Public Interest Research Group, and the Clean Air Task Force.

The data was compiled by Abt Associates Inc., a consulting firm that the Bush administration and EPA have used to analyze their air pollution policies.

Some research "suggests that power plants aren't the source of the problem" and that EPA should not impose stricter rules that could raise electricity rates, said Dan Riedinger of the Edison Electric Institute, an industry lobbying group.

The report, laced with pictures of gravestones and children clutching inhalers, takes aim at an administration proposal that would require U.S utilities to cut their emissions of sulfur dioxide and nitrogen oxides by 70 percent after 2015. Democrats and environmental groups unsuccessfully sought steeper cuts on a faster timetable.

The EPA said the report "doesn't look at the whole picture" and pointed to a suite of related rules limiting diesel and smog emissions that will have a cumulative impact.

Together, the rules "will bring nearly every community in America into attainment under our new, more protective health based air quality standards," the agency said in a statement.

The EPA estimated its new rules would result in 14,100 fewer annual deaths by 2020 from fine particles emitted by power plants that cause respiratory problems like asthma. But the environmental groups' report said enforcing rules set by the existing Clean Air Act would prevent about 18,000 annual deaths over the same period.

The report ignored the fact that power plant emissions dropped by 75 percent from 1970 to 1999 while energy use rose over 40 percent, said the Electric Reliability Coordinating Council, which represents many coal-burning utilities.

A state-by-state breakdown of pollution-related impacts is available at http://www.cleartheair.org/dirtypower.